Overview

• Mouse experiments show that respiratory viruses trigger IL-6 release in the lungs, which reawakens dormant breast cancer cells.
• Helper T cells establish an immunosuppressive niche that allows reactivated tumor cells to evade killer T-cell clearance.
• Mice lacking IL-6 resist metastatic awakening following influenza infection, confirming the cytokine’s central role.
• Registry analyses from UK Biobank and Flatiron Health report elevated cancer mortality and lung metastasis rates among COVID-19 survivors, though significance diminishes after adjusting for comorbidities.
• Experts highlight methodological weaknesses in human data; clinical trials are being planned to test IL-6 inhibitors alongside enhanced vaccination strategies.